Treatment of hydrocarbon oil



Patented Dec. 26, 1944 TREATMENT OF HYDROCARBON OIL William Schreiber, Philadelphia, Pa., assignor to The Atlantic Refining Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. -Application May 21, 1943, Serial No. 487,971

18 Claims.

This invention relates to a method for producing improved lubricating oils, and more particularly to a method for producing lubricating oils having increased film-strength and increased resistance to oxidation and sludging. The invention constitutes an improvement over the method of treating lubricating oils described in United States Patent 2,220,851, issued to me on November 5, 1940.

In the identified United States patent, I describe a process for preparing improved lubricating oils which comprises subjecting a mixture of a hydrocarbon lubricating oil, which is usually an oil having a high viscosity index, and an organic compound of trivalent phosphorus to a thermal treatment in the presence of an artificially or extraneously introduced oxidizing agent, such as air or other oxygen-containing gas, for a period of time sufficient to cause the formation of phosphorus-containing reaction products, some of which are soluble and some of which are insoluble in the oil. The process further comprises the separation of the insoluble portion of the phosphorus-containing reaction products before applicaiton of the oil as a lubricant either per se or in the form of a blend with untreated oil.

The many organic compounds of trivalent phosphorus which may be reacted with a hydrocarbon oil in accordance with the process of my earlier patent include the esters of phosphorous acid, including the alkyl, aryl, alk-aryl, and heterocyclic phosphites such as ethyl phosphite, propyl phosphite, butyl phosphite, amyl phosphite, cyclohexyl phosphite, phenyl phosphite, cresyl phosphite, xylenyl phosphite, naphthyl phosphite, ethyl phenyl phosphite, propyl phenyl phosphite, butyl phenyl phosphite, amyl phenyl phosphite, cresyl phenyl phosphite, naphthyl phenyl phosphite, ethylhexyl phosphite, furfuryl phosphite, pyridyl phosphite and the like. Esters other than the neutral or triesters may also be utilized, for example, monoand di-esters such as mono-amyl dihydrogen phosphite, dicresyl hydrogen phosphite, monophenyl dihydrogen phosphite, dibutyl hydrogen phosphite and the like.

Other organic compounds of trivalent phosphorus which may be employed in the practice of the method of my earlier patent are the phosphines such as tributyl phosphine, triamyl phosphine, triphenyl phosphine, and the alk-aryl phosphines, i. e., butyl phenyl phospfiine and the like. The amides of phosphorous acid may also be utilized, for example, monoand dibutyl phosphorous acid amide, monoand diamyl phosphorous acid amide, the aryl amides such as phenyl phosphorous acid amide, toluyl phosphorous acid amide, and the like.

Any of the foregoing compounds may also be used in the practice of the method of my present invention, which likewise involves reacting a hydrocarbon lubricating oil with an organic compound of trivalent phosphorus, but I generally use an alk-aryl phosphite and most preferably, an alk-aryl phosphite of the formula,

O-Cresyl in which R may be any aliphatic hydrocarbon group such as ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, etc., which may itself be further substituted. Exemplary of compounds in which R is further substituted are the acyl dicresyl phosphites such as ethanoyl (acetyl) dicresyl phosphite, propanoyl (propionyl) dicresyl phosphite, and the mixed alk-aryl dicresyl phosphites as amylpropyl phenyl dicresyl phosphite, amyl heptyl phenyl dicresyl phosphite, propyl cresyl ethyl dicresyl phosphite, butyl phenoxy propyl dicresyl phosphite, octyl phenoxy ethyl dicresyl phosphite, etc. Compounds of the type of thelast two compounds mentioned, that is, mixed alk-aryl dicresyl phosphites in which the aryl group is oxy substituted, are particularly suited for use in the execution of the present invention.

According to my earlier process, the mixture of hydrocarbon oil and organic compound of trivalent phosphorus are blown with air or other oxygen-containing gas throughout the course of the thermal treatment, which is continued until the formation of sludge occurs in the mixture. I have now found that a lubricating oil of even more superior characteristics, particularly as regards oxidation stability and tendency toward sludge formation, is produced when the thermal treatment is conducted in th absence of air or other oxidizing gas artificially introduced, and if the treatment is not continued to the extent of causing the formation of a separable sludge. As a result of such modified treatment, the soluble phosphorus containing compounds formed in the oil are either of a nature dissimilar to the soluble phosphorus compounds formed in an oil treated by my other process or, if they are the same compounds, they are formed in greatly increased and therefore more effective quantities.

may vary from 1 hour or less to 40 or 50 hours.

or more, depending, inter alia, upon the quantity of phosphorus compound which was mixed with the oil and the operating temperature. In general, the higher the percentage of phosphorus compound in the oil, the longer the treatment time necessary to produce an oil of the desired characteristics. For that reason I usually prefer to treat an oil containing not substantially more than of the phosphorus compound in which event the treatment period usually does not exceed 20 hours. It is to be emphasized that by my new method, no haze or insolublematter is allowed to form in the oil although it may become slightly darker in color. In order to insure'that the treatment will not be extended to the point at which sludge formation occurs, a test sample may be first run and the point of sludge formation noted. I prefer to carry the treatment of the oil very close to the sludge for mation point as indicated by the test sample.

The treated oil may be used for lubrication purposes per se, but is usually diluted with 10 to 20 parts of untreated oil prior to such use.

gel, bauxite or the like, whereby the said inhibitors or agents are adsorbed from the oil and concentrated in the adsorbent. The inhibitors or agents may then be recovered, as concentrates, by washing the adsorbent with a solvent for the inhibitors or agents.

My invention may be further illustrated by the following examples which are not to be construed as limiting the scope thereof:

(1) Hydrocarbon oil having a Saybolt Universal viscosity of 315 seconds at 100 F., an A. P. I. gravity of 29.0, and an A. S. T. M. color of 3 was admixed with about 1.5% (by volume) of Hydrocarbon oils from various sources have been treated according to the method of the present invention, and all have been found amenable thereto, the degree of oxidation inhibition being practically the same in all cases. My process is particularly valuable as applied to the treatment of paraflin base oils or oils in which the number I The phosphorus-containing compounds formed in the treated oil not only inhibit oxidation of the oil, but also increase the film-strength thereof whereas similar bearings, tested in the untreated and to a degree not exceeded by the phosphorus compounds formed by my other method.

Oil treated in accordance with the invention and containing substantial quantities of the oxidation, sludging or corrosion inhibitors orfilmstrengthening agents, as the case maybe, pro-l duced by the treating reaction described, may be subjected to selective solvent extraction whereby these'inhibitors or film-strengthening agents are concentrated in an oil fraction produced by the solvent extraction. In the extraction, solvents such as aliphatic alcohols, esters, ketones, phenols, furfural, nitrobenzene and chlorex may be used. Also, oils containing substantial quantities of the inhibitors or film-strengthening agents may be contacted with an adsorbent medium such as fullers earth, activate clay, silica octyl phenoxy ethyl dicresyl phosphite, and heated at 340 1. for 16 hours without air blowing or other agitation. During the thermal treatment, the oil'became slightly darker in color, but no haze or other insoluble material was formed. The treated oil was thereafter blended with 14 times its volume of untreated oil of the same charab'teristics as above, making a final concentration of the additive or 0.1%. A sample of the blended oil was subjected to an oxidation test comprising heating 100 cc. of the oil at 340 F. for 96 hours, air being blown through the sample at a rate of 3 liters per hour. Despite the length of the test period, only 36 mg. of sludge formed in the oil for each 10 gm. of oil subjected to the test.' when a sample of the untreated oil was subjected to the same test, 240 mg. of sludge formed in the oil per each 10 gm. of the oil.

(2) A hydrocarbon oil having a Saybolt Univernal. viscosity of 315 seconds at 100 F., an A. P. I. gravityot 29.5", and an A. S. T. M. color of 2%, thF-oil being from a difierent source than um used-rim Example 1, was treated in a. like manner? :s'ai'nple or a blend of the concentrate wast-untreated oil (same ofl as used to prepare the concentrate), which blend contained the inhibitor in'a concentration of 0.1%, was subjected to the 96-hour oxidation test together with a sample or the same oil containing no inhibitor. 48 mg. of 'sludge'formed in the uninhibited oil per each 10 gm.'of oil, while only 3 mg. formed in the blend per each 10 gm. thereof.

(3) Cadmium-silver test bearings, when im-. mersed in the blended inhibitor-containingoils of Examples 1 and 2 for 44 hours at 340 F., air

being blown through the oil at a rate of 3 liters per. 100 cc. per hour, showed no loss in weight,

oils, showed a corrosion loss or 60 mg. in weight. The-organic compound of trivalent phosphorus employedas the inhibitor in the foregoing examples is a water-insoluble reaction product of tricresyl phosphite and octyl phenoxyethanol. It

may be-prepared by admixing tricresyl phosphite with octyl 'phenoxyethanol and thereafter bringing-the mixture to a temperature suflicient to cause reaction of the ingredients, whereby there is introduced into the tricresyl phosphite at least one octyl phenoxyethanol group. The mol ratio of tricresyl phosphite to octyl phenoxyethanol may vary from 1:1 to 1:25, and is prefe'rably o'-the order of 1:1.4. The reactants may be heated at atmospheric pressure under a reflux condenser to a temperature suflicient to efiect reaction,- for example, temperatures of the order of from 200 F. to 500 F., and the resulting oilsoluble water-insoluble reaction product may be separated from the by-products of the reaction by distillation under reduced pressure, or by recrystallization front-asuitable solvent, or by washing with a solvent having selective solvent power for either-the reaction product or the undesirable acumen Although I have done most of my work using octyl phenoxy ethyl dicresyl phosphite as the oxidation inhibiting or film-strengthening agent,

it is to be understood, as brought out in the forepart hereof, that other organic compounds of trivalent phosphorus may be employed, including the alkyl phosphites, alk-aryl phosphites, mixed alkyl-aryl phosphites, organic phosphines, phosphorous acid amides and the like.

It should also be stated that the treatment described hereinabove is adapted to viscous hydrocarbon oils, i. e., lubricating oils or lubricating oil stocks produced by distillation, acid treatment, clay treatment or solvent treatment, regardless of the source of the crude oils from which the lubricating oils or stocks may have been derived. 7 7

The improved oils, produced in accordance with the present invention, may be employed in the manufacture of thickened oils or greases or may be blended with fatty oils, synthetic esters, fatty acids, chlorinated or sulfurized compounds, alkali or heavy metal soaps or other agents utilized in the production of compounded lubricants.

I claim:

1. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil components, an organic compound of trivalent phosphorus, subjecting the resulting mixture, in the absence of an oxidizing a ent introduced from an extraneous source, to a heat treatment at a temperature and for a period of time sufficient to cause the formation of soluble phosphorus-containing reaction products, said treatment being discontinued prior to the formation of an insoluble sludge.

2. The method of producing an improved lubricant which comprises forming a concentrate '01 an organic compound of trivalent phosphorus ucts but insuflicient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

3. The methodof producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil components. an organic compound of trivalent phosphorus, subjecting the resulting mixture, in the absence of an oxygen-containing gas introduced from an extraneous source, to a heat treatment at a temperature of from 300 F. to 500 F. for a period of time sumcient to cause the formation of soluble phosphorus-containing reaction products but insufllcient to cause the appearance'oi insoluble sludge.

4. The method of producing an improved lubricant which comprises forming a concentrate of an organic compound of trivalent phosphorus in a hydrocarbon oil containing lubricating oil components, heating the concentrate at a temperature between 300 and 500 F; in the absence of an oxygen-containing gas introduced from an extraneous source, for a period of time .suflicient to cause the formation of soluble'phosphorus-containing reaction products but insufilcient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

5. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil compo- V nents, from 0.25% to 50% of an organic compound of trivalent phosphorus, subjecting the resulting mixture, in the absence of an oxygen-containing gas introduced from an extraneous source, to a heat treatment at a temperature of from 300 F. to 500 F. for a period of time sufficient to cause the formation of soluble phosphorus-containing reaction products but insumcient to cause the appearance of insoluble sludge.

6. The method. of producing an improved lubricant which comprises forming a concentrate of an organic compound of trivalent phosphorus in a hydrocarbon 011 including lubricating oil components, said concentrate containing from 0.25% to 50% of the said compound, heating the concentrate at a temperature between 300 F. and 500 F., in the absence of an oxygen-containing gas introduced from an extraneous source, for a period of time sufllcient to cause the formation of soluble phosphorus-containing reaction products but insufllcient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon o l. '7. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil components, an ester of phosphorous acid, subjecting the resulting mixture, in the absence of an oxidizing agent introduced from an extraneous source, to a heat treatment at a temperature and for a period of time sumcient to cause the formation of soluble phosphorus-containing reaction products, said treatment being discontinued prior to the formation of an insoluble sludge.

8. The method of producing an improved lubricant which comprises forming a concentrate of an ester of phosphorous acid in a hydrocarbon oil containing lubricating oil components, heating the concentrate, in the absence of an oxidizing agent introduced from an extraneous source, at a temperature and for a period of time sufllcient to cause the formation of soluble phosphorouscontaining reaction products but insufilcient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

9. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating 011 components, a mixed alk'yl-aryl ester of phosphorous acid, sub- Jecting the resulting mixture, in the absence of an oxidizing agent introduced from an extraneous source, to a heat treatment at a temperature and for a period of time sufficient to cause the formation of soluble phosphorus-containing reaction products, said treatment being discontinued prior to the formation of an insoluble sludge.

A 10. The method of producing an improved lubricant which comprises forming a concentrate of a mixed alkyl-aryl ester of phosphorous acid I in. a hydrocarbon oil containing lubricating 011 components, heating the concentrate, in the absence of an oxidizing agentintroduced irom an extraneous source, at a temperature and for a period of time suflicient to cause the formation of soluble phosphorous-containing reaction products but insufflcient to cause the appearance of insolubie sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

11. The method of producing an improved lublending the thus treated concentrate with 8.

- major portion of hydrocarbon oil.

15. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil components,

from 0.25% to 50% of octyl phenoxy ethyl dicresyl phosphite, subjecting the resulting mixture, in the absence of an oxygen-containing gas introduced from an extraneous source, to a heat treatment at a temperature of from 300 F. to 500 F. for a period of time suflicient to cause the formation of soluble phosphorus-containing reaction products but insuflicient to cause the appearance of insoluble sludge.

16. The method of producing an improved lubricant which comprises forming a concentrate or octyLphenoxy ethyl dicresyl phosphite in a hy- V drocarbon oil including lubricating oil compoproducts, said treatment being discontinued prior to the formation of insoluble sludge.

12. The method of producing an improved lubricant which comprises forming a concentrate of an alk-aroxy alkyl dicresyl phosphite, in a hydrocarbon oil containing lubricating oil components, heating the concentrate, in the absence of an oxidizing agent introduced from an extraneous source, at a temperature and for a p riod of time sufiicient to cause the formation of soluble phosphorus-containing reaction products but insufficient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

13. The method of producing an improved lubricating oil which comprises addingoto a hydrocarbon oil, containing lubricating oil components, octyl phenoxy ethyl dicresyl phosphite,-subjecting the resulting mixture, in the absence of an oxygen-containing gas introduced from an extraneous source, to a heat treatment at a temperature of from 300 F. to 500 F. for a period. of time suflicient to cause the formation of soluble phosphorus-containing reaction products but insufflcicnt to cause the appearance of insoluble sludge.

- 14. The method of. producing an improved lubricant which comprises forming a concentrate of octyl phenoxy ethyl dicresyl phosphite in a hydrocarbon oil containing lubricating oil components, heating the concentrate at a temperature between 300 F. and 500 F., in the absenceof an oxygen-containing gas introduced from an extraneous source, for a period of time suflicient to cause the formation of soluble phosphoruscontaining reaction products but insumcient to cause the appearance of insoluble sludge, and

nents, said concentrate containing from 0.25% to of the said phosphite, heating the concentrate at a temperature between 300 F. and 500 7 F., in the absence of an oxygen-containing gas introduced from an extraneous source, for a period of time suflicient to cause the formation of soluble phosphorus-containing reaction products but insuflicient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

1'7. The method of producing an improved lubricating oil which comprises adding to a hydrocarbon oil, containing lubricating oil components, from 0.25% to 10% of octyl phenoxy ethyl dicresyl phosphite, subjecting the resulting mixture, in the absence of an oxygen-containing gas introduced from an extraneous source, to a heat treatment at a temperature of from 325 F. to 425 F. for a period of time suflicient to cause the formation of soluble phosphorus-containing reaction products but insuflicient to cause the appearance of insoluble sludge.

18. The method of producing an improved lu-' bricant which comprises forming a concentrate of octyl phenoxy ethyl dicresyl .phosphlte in a hydrocarbon oil including lubricating oil components, said concentrate containing from 0.25% to 10% of the said octyl phenoxy ethyl dicresyl phosphite, heating the concentrate at a temperature between 325 F. and 425 F., in the absence of an oxygen-containing gas introduced from an extraneous source, for a period of time sullicient to cause the formation of soluble phosphorus-con taining reaction products but insufficient to cause the appearance of insoluble sludge, and blending the thus treated concentrate with a major portion of hydrocarbon oil.

WILLIAM SCHREIBER.

CERTIFICATE OF CORRECTION.

Patent He. 2,565,971 December 26, 191414.;

WILLIAM scmnaEn.

It is hereby certified that error appears" in the printed specification of the above numbered patent requiring correction as follows; Page-2, sec- 0nd column, line 38,'for "was untreated" read --with untreated--; and that the said Letters Patent should. be reaiwith this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 20th day ofllarch, A; n. 1915.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

